New member researching mustard algea or pollen issue

Hope this isn't too long for my first post but I'm at my wits end. I've had my pool for 7 years, and have never had any issues, minimal maintenance absolutely no issues. Last year small amount of yellow residue, chalked up to pollen, no extra chemical requirement, problem gone. This spring, last few weeks, bigger yellow problem. I only have a 10,000gal, inground, marcite pool. I've had a few stains so put an iron cobalt stain remover in the pool. Shortly after that yellow residue and very cloudy water. Hate to brag but never had anything but crystal clear pristine water so near tears seeing my pool now. Pool place swears cloudy water unrelated to stain chemical, just coincidence. In the last 2 weeks I've poured 1/2 jug of liquid chlorine in my pool, 12oz of water clarifier, brushed my pool everyday and cleaned the filter (cartridge) every day. In the last couple of days I used a microfloc clarifier (thinking pollen), brushed, and cleaned the filter out 4 times yesterday. At the end of the day, water extremely cloudy and still yellow. I'm afraid to put more chemicals in without knowing if I'm dealing with mustard algae or pollen. Can you help?